Quantum Computing News and Discussions

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Europe’s First Quantum Computer with More Than 5K Qubits Launched at Jülich

January 18, 2022

JÜLICH, Germany, Jan. 18, 2022 — A quantum annealer with more than 5,000 qubits has been put into operation at Forschungszentrum Jülich. The Jülich Supercomputing Centre (JSC) and D-Wave Systems, a leading provider of quantum computing systems, has launched the company’s first cloud-based quantum service outside North America. The new system is located at Jülich and will work closely with the supercomputers at JSC in future. The annealing quantum computer is part of the Jülich UNified Infrastructure for Quantum computing (JUNIQ), which was established in autumn 2019 to provide researchers in Germany and Europe with access to various quantum systems. Federal Minister of Education and Research Bettina Stark-Watzinger, Minister-President of North Rhine-Westphalia (NRW) Hendrik Wüst, and European Commissioner Mariya Gabriel officially put the system into operation during a ceremony held today, at which they highlighted the importance of collaboration in the development of practical quantum applications across industry sectors and research fields.

https://www.hpcwire.com/off-the-wire/eu ... at-julich/



Credit: Forschungszentrum Jülich / Sascha Kreklau

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Research team chase down advantage in quantum race
https://phys.org/news/2022-01-team-adva ... antum.html
by University of Bristol

Quantum researchers at the University of Bristol have dramatically reduced the time to simulate an optical quantum computer, with a speedup of around one billion over previous approaches.

Quantum computers promise exponential speedups for certain problems, with potential applications in areas from drug discovery to new materials for batteries. But quantum computing is still in its early stages, so these are long-term goals. Nevertheless, there are exciting intermediate milestones on the journey to building a useful device. One currently receiving a lot of attention is "quantum advantage", where a quantum computer performs a task beyond the capabilities of even the world's most powerful supercomputers.

Experimental work from the University of Science and Technology of China (USTC) was the first to claim quantum advantage using photons—particles of light, in a protocol called "Gaussian Boson Sampling" (GBS). Their paper claimed that the experiment, performed in 200 seconds, would take 600 million years to simulate on the world's largest supercomputer.

Taking up the challenge, a team at the University of Bristol's Quantum Engineering Technology Labs (QET Labs), in collaboration with researchers at Imperial College London and Hewlett Packard Enterprise, have reduced this simulation time down to just a few months, a speedup factor of around one billion.

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Researchers set record by preserving quantum states for more than 5 seconds
https://phys.org/news/2022-02-quantum-s ... conds.html
by Argonne National Laboratory

Quantum science holds promise for many technological applications, such as building hackerproof communication networks or quantum computers that could accelerate new drug discovery. These applications require a quantum version of a computer bit, known as a qubit, that stores quantum information.

But researchers are still grappling with how to easily read the information held in these qubits and struggle with the short memory time, or coherence, of qubits, which is usually limited to microseconds or milliseconds.

A team of researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory and the University of Chicago has achieved two major breakthroughs to overcome these common challenges for quantum systems. They were able to read out their qubit on demand and then keep the quantum state intact for over five seconds—a new record for this class of devices. Additionally, the researchers' qubits are made from an easy-to-use material called silicon carbide, which is widely found in lightbulbs, electric vehicles and high-voltage electronics.

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Giant leap toward quantum internet realized with Bell state analyzer
https://phys.org/news/2022-03-giant-qua ... state.html
by Oak Ridge National Laboratory

Scientists' increasing mastery of quantum mechanics is heralding a new age of innovation. Technologies that harness the power of nature's most minute scale show enormous potential across the scientific spectrum, from computers exponentially more powerful than today's leading systems, sensors capable of detecting elusive dark matter, and a virtually unhackable quantum internet.

Researchers at the Department of Energy's Oak Ridge National Laboratory, Freedom Photonics and Purdue University have made strides toward a fully quantum internet by designing and demonstrating the first ever Bell state analyzer for frequency bin coding.

Their findings were published in Optica.

Before information can be sent over a quantum network, it must first be encoded into a quantum state. This information is contained in qubits, or the quantum version of classical computing "bits" used to store information, that become entangled, meaning they reside in a state in which they cannot be described independently of one another.

Entanglement between two qubits is considered maximized when the qubits are said to be in "Bell states."

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Researchers develop quantum gate enabling investigation of optimization problems
https://phys.org/news/2022-03-quantum-g ... blems.html
by Christian Flatz, University of Innsbruck

The development of quantum computers is being pursued worldwide, and there are various concepts of how computing using the properties of the quantum world can be implemented. Many of these have already advanced experimentally into areas that can no longer be emulated on classical computers. But the technologies have not yet reached the point where they can be used to solve larger computational problems. Therefore, researchers are currently looking for applications that can be implemented on existing platforms. "We are looking for tasks that we can compute on existing hardware," says Rick van Bijnen of the Institute of Quantum Optics and Quantum Information at the Austrian Academy of Sciences in Innsbruck. A team around Van Bijnen and the Lechner research group is now proposing a method to solve optimization problems using neutral atoms.

Software solution

To develop scientifically and industrially relevant applications for existing quantum hardware in the near future, researchers are looking for special algorithms that structurally match the strengths of a quantum platform. "This co-design of algorithms and experimental platforms allows these systems to work without error correction, which is still difficult to achieve today," explains Wolfgang Lechner from the Department of Theoretical Physics at the University of Innsbruck. The physicists envision their optimization algorithm to be implemented on neutral atoms trapped and arranged in optical tweezers. They can be programmed via the interaction of highly excited Rydberg states. To avoid the limitations of previous approaches, the physicists do not implement the algorithm directly, but use the so-called parity architecture, a scalable and problem-independent hardware design for combinatorial optimization problems, which Wolfgang Lechner developed together with Philipp Hauke and Peter Zoller in Innsbruck.

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Silicon FinFETs hosting hole spin qubits at temperatures over 4 Kelvin
https://techxplore.com/news/2022-03-sil ... ubits.html
by Ingrid Fadelli , Tech Xplore

The idea of creating a spin-based quantum computer using quantum dots was first introduced by Daniel Loss and David Di Vincenzo in 1998. Since then, countless engineers and physicists worldwide have been trying to realize their vision using existing and newly developed hardware components.

So far, silicon has proved to be among the most promising materials for creating spin-based quantum computers, as most complementary metal oxide semiconductors (CMOSs) in use today are made of silicon. Moreover, silicon can be designed to be free of nuclear spins, which are known to degrade the coherence of spin qubits in quantum computers.

Researchers at University of Basel and IBM Research-Zurich have recently explored the possibility of hosting spin qubits in silicon-based FinFETs, a class of transistors first introduced by researchers at University of California- Berkeley. Their results, published in Nature Electronics, were very promising, as they suggest that FinFETs could help to improve the scalability of quantum technologies.

"Billions of FinFETs are used in today's computer chips," Andreas Kuhlmann and Dominik Zumbühl, two of the researchers who carried out the study, told TechXplore. "Achieving scalability (i.e., going from a few tens of qubits to many millions) remains the greatest challenge for quantum computing. So, we thought: why not build a quantum computer with a platform that has successfully mastered this challenge? Furthermore, FinFETs are also excellent hosts for (hole) spin qubits and a very handy property of hole spin qubits is their spin-orbit interaction."

The spin-orbit interaction is an important property of hole spin qubits that can be very advantageous, as it allows researchers to manipulate spin states by applying an oscillating electrical signal to them. Physics theory predicts that holes in silicon FinFETs will have an unusually large spin-orbit interaction that can be electrically modulated.

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Study highlights the possibility of building wave-shape-tolerant qubit gates
https://phys.org/news/2022-04-highlight ... gates.html
by Ingrid Fadelli , Phys.org

Quantum computers, machines that leverage quantum states to perform computations and store data, could soon revolutionize the computing industry, achieving significantly greater speeds and performance than existing computers. While countless companies worldwide, including Google and IBM as well as smaller start-ups, have started working on quantum technologies, the exact architecture that will lead to their mass production remains unclear.

Researchers at Leibniz University Hannover have recently conducted a theoretical study investigating the possibility of realizing flying-qubit gates for quantum computers that are insensitive to the wave shapes of photons, and also fully preserve these shapes during processing. Their paper, published in Physical Review Letters, could serve as the basis for the development of new gates that can process entangled photonic wave packets more effectively than unentangled ones.

[weatheriscool]

Researchers generate high-quality quantum light with modular waveguide device
https://phys.org/news/2022-04-high-qual ... evice.html
by Optica

For the first time, researchers have successfully generated strongly nonclassical light using a modular waveguide-based light source. The achievement represents a crucial step toward creating faster and more practical optical quantum computers.

"Our goal is to dramatically improve information processing by developing faster quantum computers that can perform any type of computation without errors," said research team member Kan Takase from the University of Tokyo. "Although there are several ways to create a quantum computer, light-based approaches are promising because the information processor can operate at room temperature and the computing scale can be easily expanded."

In the Optica Publishing Group journal Optics Express, a multi-institutional team of researchers from Japan describe the waveguide optical parametric amplifier (OPA) module they created for quantum experiments. Combining this device with a specially designed photon detector allowed them to generate a state of light known as Schrödinger cat, which is a superposition of coherent states.

"Our method for generating quantum light can be used to increase the computing power of quantum computers and to make the information processer more compact," said Takase. "Our approach outperforms conventional methods, and the modular waveguide OPA is easy to operate and integrate into quantum computers."[/quote]

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First hybrid quantum bit based on topological insulators
https://phys.org/news/2022-04-hybrid-qu ... gical.html
by Forschungszentrum Juelich

With their superior properties, topological qubits could help achieve a breakthrough in the development of a quantum computer designed for universal applications. So far, no one has yet succeeded in unambiguously demonstrating a quantum bit, or qubit for short, of this kind in a lab. However, scientists from Forschungszentrum Jülich have now gone some way to making this a reality. For the first time, they succeeded in integrating a topological insulator into a conventional superconducting qubit. Just in time for "World Quantum Day" on 14 April, their novel hybrid qubit made it to the cover of the latest issue of the journal Nano Letters.

Quantum computers are regarded as the computers of the future. Using quantum effects, they promise to deliver solutions for highly complex problems that cannot be processed by conventional computers in a realistic time frame. However, the widespread use of such computers is still a long way off. Current quantum computers generally contain only a small number of qubits. The main problem is that they are highly prone to error. The bigger the system, the more difficult it is to fully isolate it from its environment.

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Assessing physical realism experimentally in a quantum-regulated device
https://phys.org/news/2022-04-physical- ... evice.html
by Thamarasee Jeewandara , Phys.org

In a new report now published in Nature Communications Physics, Pedro R. Dieguez and an international team of scientists in quantum technologies, functional quantum systems and quantum physics, developed a new framework of operational criterion for physical reality. This attempt facilitated their understanding of a quantum system directly via the quantum state at each instance of time. During the work, the team established a link between the output visibility and elements of reality within an interferometer. The team provided an experimental proof-of-principle for a two-spin-½ system in an interferometric setup within a nuclear magnetic resonance platform. The outcomes validated Bohr's original formulation of the complementarity principle.

Physics according to Niels Bohr

Bohr's complementarity principle states that matter and radiation can be submitted to a unifying framework where either element can behave as a wave or a particle, based on the experimental setup. According to Bohr's natural philosophy, the nature of individuality of quantum systems is discussed relative to the definite arrangement of whole experiments. Almost a decade ago, physicists designed a quantum delayed choice experiment (QDCE), with a beam splitter in spatial quantum superposition to render the interferometer to have a "closed + open" configuration, while the system represented a hybrid "wave + particle" state. Researchers had previously coupled a target system to a quantum regulator and tested these ideas to show how photons can exhibit wave-like or particle-like behaviors depending on the experimental technique used to measure them. Based on the capability to smoothly interpolate the statistics between a wave- and particle-like pattern, physicists suggested the manifestation of morphing behaviors in the same system; claiming a radical revision of Bohr's complementarity principle.

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Fault-tolerant quantum computer memory in diamond
https://phys.org/news/2022-04-fault-tol ... amond.html
by Yokohama National University

Quantum computing holds the potential to be a game-changing future technology in fields ranging from chemistry to cryptography to finance to pharmaceuticals. Compared to conventional computers, scientists suggest that quantum computers could operate many thousand times faster. To harness this power, scientists today are looking at ways to construct quantum computer networks. Fault-tolerant quantum memory, which responds well when hardware or software malfunctions occur, will play an important role in these networks. A research team from Yokohama National University is exploring quantum memory that is resilient against operational or environmental errors.

The research team reported their findings on April 27, 2022 in the journal Communications Physics.

[caltrek]

New Approach May Help Clear Hurdle to Large-scale Quantum Computing
April 29, 2022

https://www.eurekalert.org/news-releases/951249

Introduction:

(EurekAlert) Building a plane while flying it isn’t typically a goal for most, but for a team of Harvard-led physicists that general idea might be a key to finally building large-scale quantum computers.

Described in a new paper in Nature, the research team, which includes collaborators from QuEra Computing, MIT, and the University of Innsbruck, developed a new approach for processing quantum information that allows them to dynamically change the layout of atoms in their system by moving and connecting them with each other in the midst of computation.

This ability to shuffle the qubits (the fundamental building blocks of quantum computers and the source of their massive processing power) during the computation process while preserving their quantum state dramatically expands processing capabilities and allows for the self-correction of errors. Clearing this hurdle marks a major step toward building large-scale machines that leverage the bizarre characteristics of quantum mechanics and promise to bring about real-world breakthroughs in material science, communication technologies, finance, and many other fields.

“The reason why building large scale quantum computers is hard is because eventually you have errors,” said Mikhail Lukin, the George Vasmer Leverett Professor of Physics, co-director of the Harvard Quantum Initiative, and one of the senior authors of the study. “One way to reduce these errors is to just make your qubits better and better, but another more systematic and ultimately practical way is to do something which is called quantum error correction. That means that even if you have some errors, you can correct these errors during your computation process with redundancy.”

In classical computing, error correction is done by simply copying information from a single binary digit or bit so it’s clear when and where it failed. For example, one single bit of 0 can be copied three times to read 000. Suddenly, when it reads 001, it’s clear where the error is and can be corrected. A foundational limitation of quantum mechanics is that information can’t be copied, making error correction difficult.

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New control electronics for quantum computers that improve performance, cut costs
https://phys.org/news/2022-05-electronics-quantum.html
by Tracy Marc, Fermi National Accelerator Laboratory

When designing a next-generation quantum computer, a surprisingly large problem is bridging the communication gap between the classical and quantum worlds. Such computers need a specialized control and readout electronics to translate back and forth between the human operator and the quantum computer's languages—but existing systems are cumbersome and expensive.

However, a new system of control and readout electronics, known as Quantum Instrumentation Control Kit, or QICK, developed by engineers at the U.S. Department of Energy's Fermi National Accelerator Laboratory, has proved to drastically improve quantum computer performance while cutting the cost of control equipment.

"The development of the Quantum Instrumentation Control Kit is an excellent example of U.S. investment in joint quantum technology research with partnerships between industry, academia and government to accelerate pre-competitive quantum research and development technologies," said Harriet Kung, DOE deputy director for science programs for the Office of Science and acting associate director of science for high-energy physics.

[caltrek]

Dutch Researchers Teleport Quantum Information Across Rudimentary Quantum Network
May 25, 2022

Introduction:

(EurekAlert) Researchers in Delft have succeeded in teleporting quantum information across a rudimentary network. This first of its kind is an important step towards a future quantum Internet. This breakthrough was made possible by a greatly improved quantum memory and enhanced quality of the quantum links between the three nodes of the network. The researchers, working at QuTech—a collaboration between Delft University of Technology and the Netherlands Organisation for Applied Scientific Research (TNO)—are publishing their findings today in the scientific journal Nature.

The power of a future quantum Internet is based on the ability to send quantum information (quantum bits) between the nodes of the network. This will enable all kinds of applications such as securely sharing confidential information, linking several quantum computers together to increase their computing capability, and the use of highly precise, linked quantum sensors.

Sending quantum information

The nodes of such a quantum network consist of small quantum processors. Sending quantum information between these processors is no easy feat. One possibility is to send quantum bits using light particles but, due to the inevitable losses in glass fibre cables, in particular over long distances, the light particles will very likely not reach their destination. As it is fundamentally impossible to simply copy quantum bits, the loss of a light particle means that the quantum information is irrecoverably lost.

Teleportation offers a better way of sending quantum information. The protocol for quantum teleportation owes its name to similarities with teleportation in science-fiction films: the quantum bit disappears on the side of the sender and appears on the side of the receiver. As the quantum bit therefore does not need to travel across the intervening space, there is no chance that it will be lost. This makes quantum teleportation an crucial technique for a future quantum Internet.

Read more here: https://www.eurekalert.org/news-releases/953932

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Error-free quantum computing gets real

by University of Innsbruck
https://phys.org/news/2022-05-error-fre ... -real.html

In modern computers, errors during processing and storage of information have become a rarity due to high-quality fabrication. However, for critical applications, where even single errors can have serious effects, error correction mechanisms based on redundancy of the processed data are still used.

Quantum computers are inherently much more susceptible to disturbances and will thus probably always require error correction mechanisms, because otherwise errors will propagate uncontrolled in the system and information will be lost. Because the fundamental laws of quantum mechanics forbid copying quantum information, redundancy can be achieved by distributing logical quantum information into an entangled state of several physical systems, for example multiple individual atoms.

The team led by Thomas Monz of the Department of Experimental Physics at the University of Innsbruck and Markus Müller of RWTH Aachen University and Forschungszentrum Jülich in Germany has now succeeded for the first time in realizing a set of computational operations on two logical quantum bits that can be used to implement any possible operation. "For a real-world quantum computer, we need a universal set of gates with which we can program all algorithms," explains Lukas Postler, an experimental physicist from Innsbruck.

Fundamental quantum operation realized

The team of researchers implemented this universal gate set on an ion trap quantum computer featuring 16 trapped atoms. The quantum information was stored in two logical quantum bits, each distributed over seven atoms.

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Doubling up Cooper pairs to protect qubits in quantum computers from noise
https://phys.org/news/2022-06-cooper-pa ... noise.html
by Bob Yirka , Phys.org

A team of researchers affiliated with several institutions in France has developed a means of using pairs of Cooper pairs to protect qubits inside a quantum computer from external noise. In their paper published in the journal Physical Review X, the group describes how they tackled the problem of qubit sensitivity to noise and how well their approach worked when tested.

An obstacle to the development of quantum computers is external noise affecting qubits. One of the most promising approaches to dealing with noise is to delocalize the quantum information used in the computer. This is because the noise that creates problems is typically local. The idea is to delocalize where the information is stored, and the researchers developed a new way to do that.

Inside a quantum computer are superconducting circuits—their states can be described using pairs of electrons known as Cooper pairs. In such systems, the pairs tunnel through a Josephson junction. The researchers came up with a new kind of superconducting qubit in which the quantum states are nonlocalized by modifying the Josephson junction. In their setup, two Cooper pairs were allowed to tunnel through simultaneously. The junction was made using a superconducting loop that also made use of superinductors. Using this approach allowed the team to control the kinetic interference co-tunneling element. This resulted in suppressing the tunneling of undesired Cooper pairs, allowing those that were co-tunneling to pass through unharmed. The approach led to doubling the magnification of the superconducting phase.

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Theory suggests quantum computers should be exponentially faster on some learning tasks than classical machines
https://phys.org/news/2022-06-theory-qu ... tasks.html
by Bob Yirka , Phys.org

A team of researchers affiliated with multiple institutions in the U.S., including Google Quantum AI, and a colleague in Australia, has developed a theory suggesting that quantum computers should be exponentially faster on some learning tasks than classical machines. In their paper published in the journal Science, the group describes their theory and results when tested on Google's Sycamore quantum computer. Vedran Dunjko with Leiden University City has published a Perspective piece in the same journal issue outlining the idea behind combining quantum computing with machine learning to provide a new level of computer-based learning systems.

Machine learning is a system by which computers trained with datasets make informed guesses about new data. And quantum computing involves using sub-atomic particles to represent qubits as a means for conducting applications many times faster than is possible with classical computers. In this new effort, the researchers considered the idea of running machine-learning applications on quantum computers, possibly making them better at learning, and thus more useful.

To find out if the idea might be possible, and more importantly, if the results would be better than those achieved on classical computers, the researchers posed the problem in a novel way—they devised a machine learning task that would learn via experiments repeated many times over. They then developed theories describing how a quantum system could be used to conduct such experiments and to learn from them. They found that they were able to prove that a quantum computer could do it, and that it could do it much better than a classical system. In fact, they found a reduction in the required number of experiments needed to learn a concept to be four orders of magnitude lower than for classical systems. The researchers then built such a system and tested it on Google's Sycamore quantum computer and confirmed their theory.

[weatheriscool]

Atom Computing’s Neutral Atom Quantum Computer Sets Coherence Record
June 10, 2022 by Brian Wang
https://www.nextbigfuture.com/2022/06/a ... ecord.html

Atom Computing has closed a $60M in Series B funding, which brings their total funding to $80 million. They are building a larger second-generation quantum computing system that can run commercial use-cases.

Atom Computing’s record-setting qubit coherence was 40 seconds plus or minus 7 seconds. That may not seem very long compared to everyday life, but relative to quantum states, it is more than several lifetimes. Coherence times vary widely from a few milliseconds and up, depending on qubit type, hardware configurations, and operational procedures.

If the operations are less than a microsecond then the 40 second coherence time allows for 40 million quantum operations.

[weatheriscool]

The realization of measurement induced quantum phases on a trapped-ion quantum computer
https://phys.org/news/2022-06-quantum-p ... d-ion.html
by Ingrid Fadelli , Phys.org

Trapped-ion quantum computers are quantum devices in which trapped ions vibrate together and are fully isolated from the external environment. These computers can be particularly useful for investigating and realizing various quantum physics states.

Researchers at NIST/University of Maryland and Duke University have recently used a trapped-ion quantum computer to realize two measurement-induced quantum phases, namely the pure phase and mixed or coding phase during a purification phase transition. Their findings, published in a paper in Nature Physics, contribute to the experimental understanding of many-body quantum systems.

"Our methods were based on work by Michael Gullans and David Huse, which identified a measurement-induced purification transition in random quantum circuits," Crystal Noel, one of the researchers who carried out the study, told Phys.org. "The main objective of our paper was to observe this critical phenomenon experimentally, using a quantum computer."

[funkervogt]

Another important milestone in quantum computing:

In “Quantum Advantage in Learning from Experiments”, a collaboration with researchers at Caltech, Harvard, Berkeley, and Microsoft published in Science, we show that a quantum learning agent can perform exponentially better than a classical learning agent at many tasks. Using Google’s quantum computer, Sycamore, we demonstrate the tremendous advantage that a quantum machine learning (QML) algorithm has over the best possible classical algorithm. Unlike previous quantum advantage demonstrations, no advances in classical computing power could overcome this gap. This is the first demonstration of a provable exponential advantage in learning about quantum systems that is robust even on today's noisy hardware.

https://ai.googleblog.com/2022/06/quant ... -from.html

BTW, here's the difference between the more-familiar "quantum supremacy" and "quantum advantage":

Quantum Supremacy: This term still retains Preskill’s original context and is considered the first major step to prove quantum computing is feasible. Specifically, it means: “demonstrating that a programmable quantum device can solve any problem that no classical computing device can solve in a feasible amount of time, irrespective of the usefulness of the problem.” Based on the definition, this threshold has been passed since October 2019, in fact at this point it has been shown by several different companies beyond Google and this is why I refer to the current hurdles as engineering challenges rather that theoretical ones.

Quantum Advantage: Refers to the demonstrated and measured success in processing a real-world problem faster on a Quantum Computer than on a classical computer. While it is generally accepted that we have achieved quantum supremacy, it is anticipated that quantum advantage is still some years away.

Note: The above quote came from an article written only seven months ago.